Google Gmail OAuth

Google Gmail now supports the standard IMAP and SMTP protocols for accessing and sending e-mail messages. The Gmail IMAP and SMTP servers have been extended to support authorization via the industry-standard OAuth protocol. This allows third party applications to access a user's email account with their permission.
Google Gmail OAuth

Clickatell SMTP

One of seven SMS APIs offered by Clickatell. Clickatell covers over 819 networks in more than 220 countries. You will be able to send SMS messages around the world to your clients, staff or user-database. All Clickatell APIs support text, Unicode, binary SMS and flash messaging. SMTP provides connectivity from legacy server, particularly server-generated e-mail. As an industry standard used by operators for high-volume messaging, SMTP is particularly useful for notification alerts. It gives you support for extended length messages, converters, delivery acknowledgements and sender ID, and allows you to set up batch sending. SMTP further provides access to gateway escalation and queuing.
Clickatell SMTP

SendGrid

SendGrid's cloud-based email helps keep emails out of spam folders, provides a cloud service that scales with email demands, and provides email analytics to track opens and clicks. SendGrid has a Web API that allows customers to retrieve information about their account such as statistics, bounces, spam reports, unsubscribes, and other information. In addition, the Web API allows customers to create sub-accounts and control the settings of these accounts for an OEM setup. With the SendGrid API, developers can: * Get real-time web hooks for events such as bounces, clicks, and unsubscribes * Send multiple emails and customize plugins * Access parsed incoming emails with attachments * Write plugins to alter emails or deliver to other mediums * Manage subscriptions for resellers and subusers
SendGrid

Qipit

The Qipit Mobile Copy API moves digital cameras and camera phones beyond just taking pictures by enabling developers to use the camera sensor to create “scan quality” highly legible, printable, ink-on-white digital copies of anything written or printed. The technology enables developers to create a variety of applications and services ranging from logistics applications to track inventories in unconventional place, sales force automation applications to get forms and signed contracts back to headquarters and for e-tailers (and e-card services) to enable customers to add the personal touch of their own handwriting for gift cards. Other potential uses include applications and mash-ups with social networking sites to share class notes or other written information. How it works You submit a JPEG photo of anything written or printed, such as a document, note or receipt to the Qipit scanning engine. The technology transforms this picture into a crisp clear ink-on-white copy (in the form of a JPEG). The Qipit scanning engine automatically corrects for framing (crops it), compression, noise, vignetting, illumination, glare, contrast, tilt, and skew as well as motion and optical blur.
Qipit

Upside Wireless

From their site: Upside Wireless Inc. is a leading North American company that specializes in providing global mobile messaging services and applications for consumer and enterprise markets. Upside's flexible two-way SMS platform enables enterprise customers to efficiently connect existing corporate applications to the global text messaging network. For your convenience, we offer three connectivity options: SOAP, HTTP and SMTP.
Upside Wireless